Association between maternal thyroid function in early pregnancy and gestational diabetes

Abstract

Background Previous studies on the relationship between thyroid gland
function and the development of gestational diabetes mellitus (GDM) have
reported different results, leading to the need for a cohort study design with a
large sample size.
Objective: We aimed to investigate the relationship between thyroid function
in early pregnancy and GDM.
Methods: This was a prospective cohort from February 2018 to December
2020.The study took place at a tertiarymaternal and childhealth hospital. Atotal
of 36 142 pregnant women were successfully recruited The main outcome
measure was GDM.
Results: This study consisted of 26 650 pregnant women who met the inclusion
criteria, of whom 3982 (14.90%) were diagnosed with GDM, and the women
with GDM were older than their healthy counterparts (33.26 ± 4.01 vs 31.51 ±
3.76 years, P< .001). After removing potential influencing variables, we found
that increased thyroid-stimulating hormone (TSH) (adjusted odds ratio [aOR]
1.030, 95% CI 1.007, 1.054, P = .012) and subclinical hypothyroidism (aOR
1.211, 95% CI 1.010, 1.451, P = .039), but not free thyroxine or thyroid
peroxidase antibody, were associated with the occurrence of GDM. Further
analysis indicated a nonlinear relationship between TSH and GDM (P< .05):
when TSH ≤ 1.24 mIU/L, the occurrence of GDM was elevated with increasing
TSH, but when TSH > 1.24 mIU/L, this trend was not obvious.
Conclusion: High TSH might be associated with increased risk of GDM.